fix: 删除未使用的 original_args 变量

lint 失败修复：
- F841: Local variable `original_args` is assigned to but never used
- 移除日志时遗漏删除变量赋值

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

litellm/responses/litellm_completion_transformation/handler.py

@@ -94,7 +94,6 @@ class LiteLLMCompletionTransformationHandler:
                     args = None
 
                 # 检查并修复 arguments
-                original_args = args
                 fixed_args = None
 
                 if args is None: